I have been using Twitter for a little less than a year and have almost 687 followers, slowly building my following the old-fashioned way – with good tweets and re-tweets. but few are at 22k follower .. How to grow at that level

Just follow others on Twitter. They will follow you back too. Atleast 3 out of 7 will follow you back. Thus you can get Twitter followers even without a single tweet or retweet. If you need more followers fast do following others on Twitter. Don't overdo this trick. Do only 100 or less follows per hour. Try with follow suggestions made by Twitter.